3500HP 550CI Ford Boss 429 Engine – Horse Power!

550CI, 3,500HP Boss 429Giuseppe Gentile, Muscle Motors Performance, North Hollywood, CA
So we’re casually strolling through the pits of California Speedway during the most recent PSCA (Pacific Street Car Association) race, when bam! The sight of this twin turbo Boss 9 Ford hit us like a punch to the gut. Giuseppe Gentile drives an ’08 Mustang powered by this engine in PSCA’s Pro Street class. In this class, guys are allowed to build either NA or power-adder engines, and we were happy to see a few of them with turbo cars, but we weren’t expecting a turbo Boss 429. Talking with the crew, we were stunned to hear the car was built in Giuseppe’s two-car garage at his house in North Hollywood. This 2,825-pound Mustang clicks off low-6-second passes at more than 230 mph-pretty good for a backyard build.

A. Transmission
We were surprised to hear this engine is backed by a TH400 trans, not a Powerglide. “Rossler built it, and it’s bad to the bone,” Giuseppe tells us. “It’s all billet on the inside, but the case is stock. We’ve never had a problem with it.” The ProTorque converter stalls at an astronomic 7,500 rpm. Giuseppe wouldn’t divulge what rpm he shifts at, but if you want to guess for yourself, go to gentileracing.com and click on the video section.

B. Intake
From the intercooler, it’s a straight shot through the firewall into the Deeds intake manifold. Fuel spray is provided by a set of Siemens Deka 220-lb/hr fuel injectors, and the fuel pump is from Waterman courtesy of Musclemotors.com. It is capable of providing 13 gallons per minute. This engine runs on gasoline, and Giuseppe burns through 3 gallons per pass.

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C. Long-Block
CNC Motorsports supplied the block, which is based on Ford’s 385 engine family. Machining and assembly were collaborative efforts between Pettis Performance and QMP Performance Engines. Giuseppe was a little vague on the bore and stroke measurements for his engine, but a factory 460 engine measures 4.360×3.850. The compression ratio is privileged information, as are the specific details of the rotating assembly. The cylinder heads are from Pettis Performance. The Boss 429 cylinder head was basically Ford’s version of a hemispherical combustion chamber and is sometimes referred to as the Ford Hemi. These heads house Del West valves and Jesel rocker arms that are actuated by an Isky solid roller cam and Isky Red Zone lifters. The cam specs are also top secret, but Giuseppe made cryptic references to valve lift numbers above 0.800 inch. Driving the cam is a trick Danny Bee beltdrive system that costs more than some magazine writers make in a week. Google Danny Bee timing belt to see a picture. It is suitable for framing.

D. Electronics
The MSD Pro Billet front-drive distributor is powered by a Digital 7 ignition box mounted inside the car, and the engine management is by BigStuff3. Job Spetter Jr. of Turbopeople.com tuned the engine, and the car went 6.26 at 233 mph in its first full pass on the new ECM setup. Giuseppe’s fastest pass to date is 6.17 at 245.5 mph, and he says the combination has more left in it.

E. Forced Induction
Those two turbochargers are the real eye candy here. They are Precision Turbos’ Pro Mod 91s. Giuseppe was understandably tight-lipped when we asked how much boost: “A lot” was all we could pry out of him. Mounted low this way, the turbo inlets fit inside the Mustang’s foglight openings. Deeds Performance made the 304 stainless steel headers and aluminum cold-side tubing by hand. The intercooler is also from Deeds and is housed in a box where the passenger seat would be. Before each run, the crew loads this box with almost 20 pounds of ice. Pressurized air enters the intercooler at 350 degrees but leaves at an incredible 70 degrees.